LECTURE 1IntroductionSexual DifferentiationPrenatal (in utero) development of the male and female reproductive structuresThe physical difference between male and female reproductive structuresGenetic sexEstablished at fertilizationXX = femaleXY = maleHormones and Sexual Differentiation of the BrainEx. Book carrying differencesSome explanations include:Body posture, way limbs are heldFemales often fold their arms in front of the bodyMales more open postureEx. Finger lengthMen: right finger > index fingerWomen: index finger > ring fingerSexual DifferentiationY chromosome induces the indifferent gonads (neither male nor female) to become testesThis differentiation begins approximately during th 6th-7th week of gestationThe testes produce two hormones:Androgens – which will act on the Wolffian duct system to induce internal male reproduction structures and on the external genitalia to induce male external structuresMullerian duct inhibiting hormone (MDIH) – which will act on the Mullerian duct system to cause them to generateWolffian Ducts respond to androgens to form seminal vesicles, vas deferens and epididymisMullerian ducts inhibited by MDIHMale Differentiation (see chart in book)In summary the Wolffian Ducts are induced by testosterone to form the:Seminal vesiclesVas deferensEpididymisInternal StructuresEjaculatory DuctsLead to urethra and junction of ducts of seminal vesicles and vas deferensProstate GlandThin milky fluid helpful in sperm motility and buffers sperm cellsExternal genitalia in the male respond to potent androgen called dihydrotesterone to become male structures including:Scrotum, penis, and prostate glandReceptors only respond testosterone and cell changes it to DHTIClicker: If we prevented testosterone from being changed to DHT, we woud not findPenisFemale Sexual Differentiation (see book)If androgens are absent, the Mullerian ducts will develop into internal female reproductive structures including:Oviducts, uterus, and portion of the vaginaInternal structuresOvaries-Under control of FSH & LH….If no androgens are present (no hormonal input), then female external structures develop into:Clitoris, labia, and vaginaIClicker: an individual with a genotype of XXY would have…TestesHomologous StructuresIt is clear that males and females are different, but the reproductive structures develop from the exact same tissuesIf androgens are present the tissues become male structures and without androgens they become female structuresThe structures are termed homologous structuresScrotum & labia majoraPenis & clitorisCowper’s glands & Bartholin’s glandsTestes & ovariesThe Critical Role of the Y ChromosomeY chromosome directs the male reproductive system structures due to testesIt is the androgens (male hormones) from the developing testes that are criticalAndrenogenital SyndromeThe adrenogenital syndrome can affect both genders and roughly 1 in every 10,000 to 18,000 children are born with the conditionThe syndrome will cause an excess of male sex hormone to be producedAs a result, whether on a male or female, male characteristics will begin to developFor girls, it is possible the girl’s genitals will look similar to males; ambiguous genitaliaTreatment for AGS (book)LECTURE 2iClicker: With AGS (XX) we would find…OvariesiClicker: Will Mullerian ducts become internal female reproductive structures in an XX AGS child?Yes. There is no anti-Mullerian hormone being produced hereiClicker: Will the Wollfian ducts become internal male structures in a XX AGS child?No.Summary:A female with AGS will have:Ovaries, oviduct, uterus, vagina, be fertile, have some masculinization of external genitaliaFemale with XX has no androgen normal internal structuresAndrogen Insensitivity SyndromeTwo to five out of 100,000 births will have complete syndromeSome will have partial or mild formAll individuals will have the genotype XYReceptors are the key to this syndromeCells of body do not respond to androgens from the abdominal testesWollfian Ducts are insensitive to male hormones (androgens), no male internal structures will occur except testesNo internal male structuresiClicker: Will an individual with AIS have female internal organs?NoExternal Structures of MalePenisErectile tissueCorpora cavernosa penisCorpus spongiosum penisUrethraErection is a vascular phenomenaScrotumFunctioniClicker: Through which part of the penis does the urethra pass through?Corpus spongiosum penisLECTURE 3Male CircumcisionStudy done in Africa: Male circumcision significantly reduces the incidence of male HIV infection. MC protects males from infection by HIV infected partnersNo protection from femalesInner mucosa of foreskin is rich in HIV target cellsExternal foreskin/shaft keratinized and not vulnerableAfter circumcision, only vulnerable mucosa is urethra meatusMoist sub-preputial space increase HIV survivalMC Continued..Also lowers the risk of other STDs, penile cancer, and infant urinary tract infectionIn female partners, it reduces the risk of cervical cancer, genital ulceration, bacterial vaginosis, trichomoniasis, and HPVDecisions of the American Academy of Pediatrics from 1971-20121971, 1975, 1983 - There was no absolute medical indication for routine circumcision1999 - Male circumcision could reduce risk of UTIs and has other potential medical benefits and advantages and disadvantages**Ideas are always changingThe US has the highest rate of MC, however numbers have fallenRates vary by part of the country, religion, ethnicity, etcInternal Structures of MaleTestesLeydig cells – produce male hormones-androgensSeminiferous tubules-sperm productionBoth of these activities under control of LH and FSH (gonadotropins) from anterior pituitaryEpididymisSperm mature here for approximately 10 daysVas DeferensAmpulla is storage area for sperm cellsSeminal VesiclesThick mucous secretion essential for motility of sperm cellsEjaculatory DuctsLead to urethra and junction of ducts of seminal vesicles and vas deferensProstate GlandThin milky fluid helpful in sperm motility and buffers sperm cells while in female tractCowper’s GlandsPre-ejaculatory emissionExternal Structures of FemaleExternal Structures are called the VulvaLabia majoraLabia minoraForms protective hood or prepuce of clitorisClitorisCorpora cavernosa clitoridis (erectile tissue as in the male)Internal Structures of FemaleVestibule of the VaginaUrethral orificeVaginal orificeHymen: thin membrane that covers vaginal orifice to varying
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